California invested heavily in solar power. Now there's so much that other states are sometimes paid to take it - Los Angeles Times

On 14 days during March, Arizona utilities got a gift from California: free solar power.
Well, actually better than free. California produced so much solar power on those days that it paid Arizona to take excess electricity its residents werenâ€™t using to avoid overloading its own power lines.
It happened on eight days in January and nine in February as well. All told, those transactions helped save Arizona electricity customers millions of dollars this year, though grid operators declined to say exactly how much. And California also has paid other states to take power

The number of days that California dumped its unused solar electricity would have been even higher if the state hadnâ€™t ordered some solar plants to reduce production â€” even as natural gas power plants, which contribute to greenhouse gas emissions, continued generating electricity.

Now that I have had more time to think about this, most likely someone took a coal fired power plant, and converted it to natural gas, hence the boiler. It would still be a pretty old plant for this to be the case.

Think about it: in most plans offered by CA utilities the flexible rates are the highest when sun shines the most. I run pool pump in the early morning hours and avoid running AC after 2pm because the rate jumps up at 10am and then even higher at 2pm. So they are having a surplus (and paying other states to take it) but still won't lower rates for the state's residents, the very people who paid for all that fancy stuff. Instead of texting me with "hey, run your pool pump and AC between 12am and 4pm tomorrow - help us get rid of surplus and save some coin for yourself" they inform me that "there will be a 60-cent-per-kWh surcharge between 2pm and 7pm tomorrow, enjoy".

Strawman, part of the problem is that the daytime oversupply is unpredictable and depends on temperature and cloud cover among other things. As it says in the article, you may have benefited from daytime surplus during

8 days in January
9 days in February
14 days in March

So: Are you willing to let the utility company take control of your pool pump and AC so that they can time-shift the usage to surplus hours, whenever they may occur? This is a tricky problem, both technically and sociologically. Some people are even concerned about privacy. For sure there may be safety and comfort concerns with equipment starting and stopping at random times.

Of course, it does not help that the utility companies are gaming the system, including trying to make you pay more per kWh to make up for lower quantities used, and even for being a good citizen that time shifts, as was the case in the example. Greed is always a problem. So far the "smart grid" has been mostly a ruse to fleece the customers.

Strawman, part of the problem is that the daytime oversupply is unpredictable and depends on temperature and cloud cover among other things. As it says in the article, you may have benefited from daytime surplus during

8 days in January

9 days in February

14 days in March

So: Are you willing to let the utility company take control of your pool pump and AC so that they can time-shift the usage to surplus hours, whenever they may occur? This is a tricky problem, both technically and sociologically. Some people are even concerned about privacy. For sure there may be safety and comfort concerns with equipment starting and stopping at random times.

Why go to the extreme of taking control of user's equipment when simply sending a pricing signal should be sufficient? I now have a smart meter and a device which reads it via wi-fi and feeds the data to a website where it shows pricing, usage, etc. So I know what costs when in real time.

Short-term temperature and cloud cover prediction is very reliable (and I believe they are already using it to announce "smart days" 1 day in advance).

As zzyzzx probably knows, there is a program in MD that gives people lower rates if they are willing to let the local utility narrow the window that their ac systems run. I believe that they guarantee that the place will not get outside of some preset limits.
A major challenge for utilities is just to get people to use some sort of thermostat that will allow the house temperature to rise in summer or lower in winter while nobody is home. Most people are too lazy to program a thermostat - thus the success of nest.
Straw Man's idea of having an automated pricing signal and appliances that respond in some intelligent pre-programmed way would be the best scenario. This is a much talked about solution to the grid variability of renewables. It could be applied to e-cars that are plugged in at work or home. It could be applied with some amount of consumer retraining with dishwashers, and some success with refrigerators. However, that is a whole new level of complication that most people will not implement in the foreseeable future.

Of course, it does not help that the utility companies are gaming the system, including trying to make you pay more per kWh to make up for lower quantities used, and even for being a good citizen that time shifts, as was the case in the example. Greed is always a problem. So far the "smart grid" has been mostly a ruse to fleece the customers.